Method for carrying object to be processed

ABSTRACT

A method for carrying an object to be processed used for a processing apparatus which comprises a plurality of process chambers including a specific process chamber for a process in which the object in process is easily contaminated and a carrying mechanism having two picks. The method includes a plurality of carrying steps wherein the object in process is sequentially carried from one chamber to another among the plurality of process chambers. One of the two picks is used in carrying steps up right before carrying the object into the specific process chamber, and the other pick is used in the step of carrying the object into the specific process chamber and the later carrying steps.

FIELD OF THE INVENTION

The present invention relates to a method for transferring an object tobe processed in a processing system performing a specified process onthe object such as a semiconductor wafer and the like.

BACKGROUND OF THE INVENTION

Generally, when manufacturing a semiconductor device, a process forforming various thin films, a reforming process, an oxidation/diffusionprocess, an annealing process, an etching process and the like aresequentially and repeatedly carried out on a semiconductor wafer. Forexample, multilayer thin films can be formed on a semiconductor wafer.

For example, in a single wafer processing system, a plurality of processchambers is connected in common to a single transfer chamber in order tocontinuously perform the above various processes, thereby forming aso-called cluster processing apparatus. Further, a semiconductor waferis transferred, so to speak, from one processing space to another,thereby sequentially and efficiently performing necessary processes inrespective process chambers.

An example of a conventional processing system including such a clusterprocessing apparatus will be described with reference to FIG. 7.

As shown in FIG. 7, the processing system has a vacuum processingapparatus, wherein four process chambers 104A to 104D are connected to acommon transfer chamber 102 of, e.g., a hexagon shape via gate valves106, respectively. Further, a rectangular shaped loading transferchamber 110 is connected to the common transfer chamber 102 via two loadlock chambers 108A and 108B.

Gate valves 106 are interposed in coupling portions between the loadlock chambers 108A and 108B and the common transfer chamber 102 and incoupling portions between the load lock chambers 108A and 108B and theloading transfer chamber 110, respectively. Further, coupled to theloading transfer chamber 110 are, e.g., three introduction ports 112 formounting a cassette capable of accommodating plural sheets ofsemiconductor wafers and an orienter 114 for performing a positionalignment of a semiconductor wafer W.

In addition, installed in the loading transfer chamber 110 is a loadingcarrying mechanism 116 which has two picks 116A and 116B for supportingthe semiconductor wafer W and is contractible, extensible, revolvable,straightly movable vertically and horizontally. Further, disposed in thecommon transfer chamber 102 is a carrying mechanism 118 which has twopicks 118A and 118B for supporting the semiconductor wafer W and iscontractible, extensible and revolvable.

Herein, supposing that processes are performed on the semiconductorwafer W in respective process chambers 104A to 104D in that order, thesemiconductor wafer W is transferred from the introduction port 112 asindicated by arrows. That is, the wafer W is transferred from, e.g., thecentral introduction port 112 to the orienter 114 while being supportedby the pick 116A or 116B of the loading carrying mechanism 116. Theposition of the wafer W is aligned in the orienter 114 and thensupported again by the pick 116A or 116B to be transferred into any oneof the load lock chambers, e.g., the load lock chamber 108A. The wafer Wtransferred into the load lock chamber 108A is sequentially transferredfrom one chamber to another to pass through the respective processchambers 104A to 104D in that order by the pick 118A or 118B of thecarrying mechanism 118 in the common transfer chamber 102. Necessaryprocesses are carried out on the wafer W in the respective processchambers 104A to 104D. Then, the wafer W on which various processes havebeen completely performed is unloaded into the loading transfer chamber110 via any one of the load lock chambers, e.g., the other load lockchamber 108B in this case and, thereafter, returns to the originalintroduction port 112.

In the respective carrying mechanisms 116 and 118, one of two picks iskept empty to improve a throughput. A wafer already mounted oraccommodated in a place is picked up by an empty pick to thereby makethe place empty. Then, a wafer supported by the other pick is mounted oraccommodated in the above empty place. Accordingly, the wafers aresmoothly exchanged, thereby improving the throughput.

Furthermore, as a conventional technique for preventing crosscontamination, there is a processing system including a plurality ofprocess chambers and a carrying mechanism having a plurality of picksbeing assigned to each process chamber (see, for example, pages 3 and 4,FIGS. 1 and 2 of Japanese Patent Laid-open Application No. H7-122612).In accordance with the technique, contaminants generated in any step(process chamber) do not affect other steps even though a wafer istransferred between process chambers.

SUMMARY OF THE INVENTION

However, a process in which a semiconductor wafer W can be easilycontaminated may be performed in the process chambers 104A to 104D. Forexample, in case of performing a film forming process of a thin metalfilm such as a Cu film, a Ti film or a W (tungsten) film, such a kind ofmetal particle can be attached to the surface of the wafer. The metalparticle serves as a nucleus, which can develop an abnormal growth of afilm in a CVD film forming process. Further, another film is notdeposited on a particle attached portion. Furthermore, particularly a Cuparticle has a large diffusion coefficient in a Cu oxide film to therebylower a dielectric constant of a SiO₂ film.

For example, when a film forming process for forming the thin metal filmis performed in the process chamber 104C, if the respective picks 116A,116B, 118A and 118B are operated while improving the throughput is thetop priority of the operation as described above, all the respectivepicks 116A, 116B, 118A and 118B can support a wafer on which a processis completed in the process chamber 104C. Accordingly, particles of themetal film attached on a rear surface and the like of a wafer on which aprocess is completely performed can be attached to the picks 116A, 116B,118A and 118B and, therefore, the wafer itself can be contaminated bythe particles of the metal film when the wafer W is supported by thecontaminated picks before being loaded into the process chamber 104C.Further, the picks may be contaminated by simply inserting the picksinto the process chamber 104C performing the film forming process forforming the metal film.

The present invention is conceived for the purpose of effectivelysolving the above-described cross contamination problems. It is,therefore, an object of the present invention to provide a method fortransferring an object to be processed, which is capable of preventingcross contamination (transmission of contamination) from occurring eventhough a throughput may be sacrificed.

In accordance with the present invention, there is provided a method fortransferring an object to be processed in a processing apparatus, whichhas a number of process chambers including a specified process chamberfor performing a process subject to contamination on the object; and acarrying mechanism having two picks, the method including a plurality ofcarrying steps of sequentially transferring the object from one chamberto another among the process chambers, wherein one pick of the two picksis used in carrying steps till right before the object is loaded intothe specified process chamber, and the other pick of the two picks isused in a carrying step of loading the object into the specified processchamber and any subsequent carrying step for the object.

Since only one pick is used till right before the object is loaded intothe specified process chamber in which contamination may easily occurand the other pick is used from the moment when the object is loadedinto the specified process chamber and transferred thereafter, itbecomes possible to control to the utmost cross contamination(contamination transmission) induced via the object and the picks.

In this case, preferably, the present invention method further includesa delivery step of conveying the object from the one pick to the otherpick, the delivery step including the steps of placing the object on abuffer mechanism by the one pick; and moving the other pick to pick theobject placed on the buffer mechanism.

In accordance with the present invention, there is further provided amethod for transferring an object to be processed in a vacuum processingapparatus, which has a number of process chambers including a specifiedprocess chamber for performing a process subject to contamination on theobject; a common transfer chamber which is connected in common to therespective process chambers; a carrying mechanism having two picks andprovided in the common transfer chamber; a buffer mechanism fortemporarily supporting the object and provided in the common transferchamber; and one or more transfer ports for loading or unloading theobject into or from the common transfer chamber, the method including aplurality of carrying steps in which the object is sequentiallytransferred from one chamber to another among the process chambers,wherein one pick of the two picks is used in carrying steps till rightbefore the object is loaded into the specified process chamber, and theother pick of the two picks is used in a carrying step of loading theobject into the specified process chamber and any subsequent carryingstep for the object; and a delivery step of conveying the object fromthe one pick to the other pick by employing the buffer mechanism.

Also in this case, since the pick used for transferring the object tillright before it is loaded into the specified process chamber performinga process in which contamination may easily occur on the object isdifferent from the pick used when the object is loaded into thespecified process chamber and transferred thereafter, it becomespossible to control to the utmost cross contamination (contaminationpropagation) caused via the object and the picks.

In accordance with the present invention, there is still furtherprovided a method for transferring an object to be processed in aprocessing system having plural vacuum processing apparatuses connectedvia one or more pass portions, each vacuum processing apparatusincluding a number of process chambers; a common transfer chamberconnected in common to the respective process chambers; and a carryingmechanism having two picks and provided in the common transfer chamber,wherein one process chamber of the processing system is a specifiedprocess chamber which performs a process subject to contamination on anobject to be processed; a buffer mechanism for temporarily supportingthe object is provided in a common transfer chamber connected to thespecified process chamber or in a pass portion communicating with thecommon transfer chamber; and one of common transfer chamber is providedwith one or more transfer ports for loading or unloading the objectthereinto or therefrom, the method including a plurality of carryingsteps in which the object is sequentially transferred from one chamberto another among the process chambers, wherein one pick of the two picksis used in carrying steps till right before the object is loaded intothe specified process chamber, and the other pick of the two picks isused in a carrying step of loading the object into the specified processchamber and any subsequent carrying steps for the object; and a deliverystep of conveying the object from said one pick to the other pick byemploying the buffer mechanism.

Also in this case, since the pick used for transferring the object tillright before it is loaded into the specified process chamber performinga process in which contamination may easily occur on the object isdifferent from the pick used when the object is loaded into thespecified process chamber and transferred thereafter, it becomespossible to control to the utmost cross contamination (contaminationtransmission) induced via the object and the picks.

Preferably, at least two object supporting mechanisms for supporting theobject are provided in the pass portion; the object is supported by oneof the object supporting mechanisms before being loaded into thespecified process chamber; and the object is supported by another objectsupporting mechanism after being processed in the specified processchamber.

Further, preferably, the pass portion is provided with a gate valve forcontrolling common transfer chambers coupled via the pass portion tocommunicate with or to be isolated from each other; and each of theprocess chambers is provided with a gate valve for controlling a commontransfer chamber connected thereto to communicate therewith or to beisolated therefrom; and wherein when the gate valve of the pass portionis closed, only one of the gate valves of process chambers connected toeach common transfer chamber which is isolated by the pass portion isselectively opened; and when the gate valve of the pass portion isopened, only one of the gate valves of process chambers connected tocommon transfer chambers which communicate with each other by the passportion is selectively opened.

In this case, it is possible to certainly prevent such a problem ascontamination occurring by mixing different processing gases used indifferent process chambers.

Furthermore, preferably, the delivery step includes the steps of placingthe object on the buffer mechanism by said one pick; and moving theother pick to pick the object placed on the buffer mechanism.

Moreover, preferably, the number of transfer ports is two, one of thetransfer ports being used exclusively for loading and the other transferport being used exclusively for unloading.

In this case, preferably, load lock chambers, each having a vacuum stateand an atmospheric pressure state alternately therein, are respectivelyconnected to the two transfer ports via gate valves; and a loadingtransfer chamber provided with a loading carrying mechanism having twopicks is connected in common to load lock chambers via gate valves; andwherein one pick of the loading carrying mechanism is used when theobject is loaded from the loading transfer chamber to the load lockchambers; and the other pick of the loading carrying mechanism is usedwhen the object is unloaded from the load lock chambers to the loadingtransfer chamber.

In addition, for example, a process of depositing a thin metal film onthe object is carried out in the specific process chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a schematic diagram showing a configuration of anexemplary processing system for performing a transferring method inaccordance with the present invention;

FIG. 2 shows a perspective view illustrating an exemplary buffermechanism;

FIG. 3 describes a schematic diagram showing a configuration of anexemplary processing system in accordance with a modified preferredembodiment of the present invention;

FIG. 4 sets forth a perspective view illustrating a pass portion alsoserving as a buffer mechanism;

FIG. 5 depicts an explanatory diagram explaining operations in the passportion;

FIG. 6 illustrates a schematic diagram showing a configuration of anexemplary processing system in accordance with another modifiedpreferred embodiment of the present invention; and

FIG. 7 shows an exemplary conventional processing system including acluster processing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, there will be described in detail a method for transferringan object to be processed in accordance with a preferred embodiment ofthe present invention with reference to accompanying drawings.

FIG. 1 is a schematic diagram showing a configuration of an exemplaryprocessing system for performing a transferring method in accordancewith the present invention and FIG. 2 is a perspective view illustratingan exemplary buffer mechanism.

As shown in FIG. 1, a processing system 30 has a vacuum processingapparatus, wherein four evacuable process chambers 4A to 4D are arrangedto surround a single common transfer chamber 2 of, e.g., a hexagon shapeand connected thereto via respective gate valves 6. The respectiveprocess chambers 4A to 4D are provided with susceptors 32A to 32D formounting a semiconductor wafer W, i.e., an object to be processed andare configured to perform specified processes on the semiconductor waferW. Further, a rectangular shaped loading transfer chamber 10 isconnected to the common transfer chamber 2 via two evacuable load lockchambers 8A and 8B.

Gate valves 6 are respectively interposed in coupling portions betweenthe load lock chambers 8A and 8B and the common transfer chamber 2 andin coupling portions between the load lock chambers 8A and 8B and theloading transfer chamber 10. Further, coupled to the loading transferchamber 10 are, e.g., three, introduction ports 12 for mounting acassette capable of accommodating plural sheets of semiconductor wafersand an orienter 14 for performing a position alignment of thesemiconductor wafer W. The orienter 14 in the preferred embodimentperforms the position alignment by way of optically obtaining aneccentric amount while rotating the semiconductor wafer W.

In addition, disposed in the loading transfer chamber 10 is a loadingcarrying mechanism 16 which has two picks 16A and 16B for supporting thesemiconductor wafer W and is contractible, extensible, rotatable,straightly movable vertically and horizontally. Further, disposed in thecommon transfer chamber 2 is a carrying mechanism 18 which has two picks18A and 18B for supporting the semiconductor wafer W and iscontractible, extensible and rotatable.

Herein, a transfer port 34 of a coupling portion between the commontransfer chamber 2 and either one of the two load lock chambers, e.g.,the load lock chamber 8A, is exclusively used as a loading port forloading the semiconductor wafer into the common transfer chamber 2. Onthe other hand, a loading port 36 of a coupling portion between thecommon transfer chamber 2 and the other load lock chamber 8B is usedexclusively as an unloading port for unloading the semiconductor waferout of the common transfer chamber 2.

A buffer mechanism 38 for temporarily supporting the semiconductor waferW is disposed in one corner of the common transfer chamber 2. The buffermechanism 38 has an elevation rod 40 vertically moving, a plate shapedbuffer base 42 disposed at a top end of the elevation rod 40 and, e.g.,three, supporting pins 44 protruded on the buffer base 42, as shown inFIG. 2. The top ends of the three supporting pins 44 are configured tosupport the rear surface of the wafer W.

In the following, there will be described a method for transferring anobject to be processed used for the processing system 30 configuredabove.

It is assumed that a process for depositing a thin metal film, e.g., aCu film, in which contamination can easily occur on the semiconductorwafer W, is carried out in the process chamber 4C. The process chamber4C in which the above process is performed will be treated as aspecified process chamber. Further, the term “specified” is used hereinsimply to distinguish the chamber from the other process chambers.

When transferring the semiconductor wafer W on which a film formingprocess of a thin metal film is carried out in the process chamber 4C,unnecessary thin metal films attached on, e.g., the rear surface of thewafer W may be attached (transmitted) to the picks. Accordingly, in thepresent preferred embodiment, only one pick is exclusively employed as acontamination pick. The other pick is exclusively employed as a cleaningpick until right before the wafer W is loaded into the specified processchamber 4C. The cleaning pick may be contaminated by simply beinginserted into the specified process chamber 4C. Accordingly, in thepresent preferred embodiment, the contamination pick is used also whenthe wafer W is loaded into the specific process chamber 4C. Further, ifthe contamination pick is inserted into the process chamber thatperforms a process right before a depositing process of a thin metalfilm, i.e., the process chamber 4B, the inside of the process chamber 4Bmay be contaminated. Accordingly, in the present preferred embodiment,the buffer mechanism 38 is used in performing an operation of deliveringthe semiconductor wafer from the cleaning pick to the contaminationpick.

However, under the above condition, supposing that processes areperformed on the semiconductor wafer W in the respective processchambers 4A to 4D in the order named, the semiconductor wafer W istransferred as indicated by arrows. At this time, the wafer is unloadedfrom a cassette (including a carrier) installed in one of the threeintroduction ports 12, e.g., the central introduction port 12. Further,one of the two load lock chambers 8A and 8B, e.g., the load lock chamber8A, is used for loading the wafer W before the process begins in thespecified process chamber 4C and the other load lock chamber 8B is usedfor unloading the wafer W after the process is completed in thespecified process chamber 4C.

Furthermore, in the respective carrying mechanisms 16 and 18, one pick16A or 18A of the two picks is employed as the cleaning pick and theother pick 16B or 18B is employed as the contamination pick. In thedrawing, the route used by the cleaning pick is represented by blackarrows and the route used by the contamination pick is indicated bywhite arrows.

As shown in FIG. 1, the process chambers 4A to 4D accommodate the wafersW, respectively. In this case, it is assumed that the process iscompleted or about to be completed in each of the process chambers 4A to4D.

<Transfer Operations in the Loading Transfer Chamber 10>

First, operations in the loading transfer chamber 10 will be described.The wafer W accommodated in the load lock chamber 8B after beingprocessed in all process chambers 4A to 4D is transferred to the centralintroduction port 12 along a transfer route X1 to be accommodatedtherein by the contamination pick 16B of the loading carrying mechanism16.

Further, the unprocessed wafer W of the central introduction port 12 istransferred to the orienter 14 along a transfer route X2 by the cleaningpick 16A. The wafer W is position aligned in the orienter 14 and isaccommodated in the other load lock chamber 8A by the cleaning pick 16Aagain. The above operations are repeatedly carried out whenever theprocess is performed on the wafer W.

<Transfer Operations in the Common Transfer Chamber 2>

Hereinafter, there will be described the wafer transfer operations inthe common transfer chamber 2.

1. First, the contamination pick 18B of the carrying mechanism 18 movesto pick a wafer W on which a process is completed in the process chamber4D and puts it in the empty load lock chamber 8B for a contaminatedmember after moving along a transfer route Y1.

2. Then, the contamination pick 18B moves to pick a wafer W on which aprocess is completed in the specified process chamber 4C and loads itinto the empty process chamber 4D after moving along a transfer routeY2. Thereafter, a process is started in the process chamber 4D.

3. At this time, supported on the buffer mechanism 38 is the wafer W onwhich a process is already completed in the process chamber 4B. Thecontamination pick 18B moves to pick the wafer W mounted on the buffermechanism 38 and loads it into the empty specified process chamber 4Cafter moving along a transfer route Y3. Thereafter, a process is startedin the specific process chamber 4C.

4. Next, the cleaning pick 18A moves to pick the wafer W on which aprocess is completed in the process chamber 4B and puts it on the emptybuffer mechanism 38 after moving along a transfer route Y4. The wafer Wis standing by there.

5. Next, the cleaning pick 18A moves to pick the wafer W on which aprocess is completed in the process chamber 4A and transfers it into theempty process chamber 4B after moving along a transfer route Y5.Thereafter, a process is started in the process chamber 4B.

6. Next, the cleaning pick 18A moves to pick the unprocessed wafer Wthat is standing by in the load lock chamber 8A for a clean member andloads it into the empty process chamber 4A after moving along a transferroute Y6. Thereafter, a process is started in the process chamber 4A.Further, when loading/unloading the semiconductor wafer W, thecorresponding gate valves 6 are operated to be opened/closed.

Further, whenever the process is completed on the semiconductor wafer Win the respective process chambers 4A to 4D, the above operations arerepeatedly carried out.

As described above, the contamination picks 16B and 18B have to be usedin the steps of transferring the wafer W into the specified processchamber 4C, and transferring the wafer which has a thin metal filmformed thereon in the specified process chamber 4C to thereby mostlikely cause metal contamination. On the other hand, the cleaning picks16A and 18A are used in the steps prior to the step of transferring thewafer W. By separately using the picks as described above, it becomespossible to prevent to the utmost cross contamination (contaminationtransmission) from occurring.

Moreover, the above transferring order is just an example and thetransferring order in the process chambers 4A to 4D is not limitedthereto. In every transfer route, the wafer on which a process iscompleted in the process chamber of the former step is temporarilysupported by the buffer mechanism 38 up until right before the wafer isloaded into the process chamber performing a process in whichcontamination may easily occur on the wafer and, at this time, the waferis transferred between the cleaning pick 18A and the contamination pick18B. Accordingly, as described above, the cleaning pick 18A is preventedfrom being contaminated and, as a result, the wafer W can be preventedfrom being contaminated before being processed in the specified processchamber 4C.

<Modified Preferred Embodiment of the Processing System>

In the above-described preferred embodiment, there is described thetransferring method in the processing system having the vacuumprocessing apparatus in which the plurality of process chambers 4A to 4Dare connected to the single common transfer chamber 2. However, thepresent invention is not limited to such a kind of processing system.For example, the present invention can be applied to a processing systemconfigured in a manner that connects a plurality of common transferchambers (vacuum processing apparatuses).

FIG. 3 is a schematic diagram showing a configuration of an exemplaryprocessing system in accordance with a modified preferred embodiment;FIG. 4 is a perspective view illustrating a pass portion (relay portion)also serving as a buffer mechanism; and FIG. 5 is an explanatory diagramexplaining operations in the pass portion. The mechanism of the passportion is represented in detail in Japanese Patent Application No.2002-047509. Further, like reference numerals designate like partshaving substantially identical functions and configurations in FIGS. 1and 3.

Further, also in the present preferred embodiment, it is supposed that aprocess for forming a thin metal film that may cause contamination isperformed in the specified process chamber 4C.

In a processing system 50 shown in FIG. 3, an additional second commontransfer chamber 20 of a polygon, e.g., an irregular heptagon, isinterposed between the first common transfer chamber 2 and the two loadlock chambers 8A and 8B in the processing system 30 shown in FIG. 1. Twoprocess chambers 4E and 4F are connected to the second common transferchamber 20 via gate valves 6, respectively. Further, a pass portion 22capable of making both the common transfer chambers 2 and 20 communicatewith each other and temporarily supporting a wafer W is interposedbetween the second common transfer chamber 20 and the first commontransfer chamber 2 to be connected thereto. When transferring the waferW, the wafer is temporarily supported in the pass portion 22. As shownin FIG. 3, the first common transfer chamber 2 is also shaped as anirregular heptagon to connect the pass portion 22 thereto. A gate valve6 is disposed in a joint between the first common transfer chamber 2 andthe pass portion 22 whereby the common transfer chambers 2 and 20 can bemade to communicate with each other or be blocked from each other.

In the same way, susceptors 32E and 32F for supporting the wafer W aredisposed in the two process chambers 4E and 4F, respectively. Further,also in the second common transfer chamber 20, there is installed acarrying mechanism 24 which has two picks 24A and 24B and iscontractible, extensible and rotatable. Further, the wafer iseffectively transferred by the same operations as described above.

Furthermore, a transfer port 52 disposed in the coupling portion betweenthe second common transfer chamber 20 and one of the two load lockchambers, e.g., the load lock chamber 8A, is used exclusively as aloading port for loading the semiconductor wafer into the second commontransfer chamber 20. On the other hand, a transfer port 54 disposed inthe coupling portion between the second common transfer chamber 20 andthe other load lock chamber 8B is used exclusively as an unloading portfor unloading the semiconductor wafer out of the second common transferchamber 20.

In the processing system 50, the buffer mechanism 38 shown in FIG. 1 isnot provided in the first common transfer chamber 2. The pass portion 22also performs the function of the buffer mechanism 38.

As shown in FIGS. 4 and 5, two object supporting mechanisms 56 and 58are disposed in the central portion of the pass portion 22 and a pair ofobject supporting mechanisms 60 is disposed outside them. The two objectsupporting mechanisms 56 and 58 positioned in the central portion havebase plates 56A and 58A formed in an approximate U-shape, respectively.Respective three supporting pins 56B and 58B are disposed to beprotruded upward on the respective base plates 56A and 58A. The centralportions of the rear surfaces of the wafers W can be respectively,separately and independently supported by respective groups of thesupporting pins 56B and 58B. As shown in FIG. 4, the U-shaped baseplates 56A and 58A are inserted to be fitted to and placed slightlyapart from each other. Further, as shown in FIG. 5, the base plates 56Aand 58A are respectively connected to top ends of elevation rods 56C and58C which are extended from below to thereby move vertically, separatelyand independently. Further, bellows (not shown) are disposed in the baseportions of the elevation rods 56C and 58C. Accordingly, the elevationrods 56C and 58C can move vertically while maintaining airtightness ofthe inside of the pass portion 22.

As described above, a single wafer W can be supported by either of thetwo object supporting mechanisms 56 and 58. FIG. 5 shows a state wherethe object supporting mechanism 56 supports a single wafer W.

As a buffer function, a wafer W is supported by either one of the objectsupporting mechanisms 56 and 58, e.g., the object supporting mechanism56 (partially indicated by oblique lines in FIG. 4), right before isloaded into the specified process chamber 4C. Further, the other objectsupporting mechanism 58 supports a wafer W on which a process iscompleted in the specified process chamber 4C. That is, the objectsupporting mechanism 58 functions as an object supporting mechanism fora contaminated member.

Meanwhile, the object supporting mechanism 60 positioned outside boththe object supporting mechanisms 56 and 58 has a pair of supportingplates 60A on the left and the right and elevation rods 60B forsupporting the supporting plates 60A at the top ends. The supportingplates 60A can move vertically while supporting the peripheral portionof the rear surface of the wafer W. Disposed also in the base portionsof the elevation rods 60B are bellows (not shown). Accordingly, theelevation rods 60B are vertically movable while maintaining airtightnessof the inside of the pass portion 22.

The object supporting mechanism 60 supports the wafer W at a higherposition, as shown in FIG. 5. In this case, the object supportingmechanism 60 is used when the wafer W is loaded from the second commontransfer chamber 20 to the first common transfer chamber 2. That is, theobject supporting mechanism 60 functions as an object supportingmechanism for a clean member.

That is, while the object supporting mechanism 60 for a clean membersupports a wafer W at a higher position, under the wafer W, the objectsupporting mechanism 56 for buffering temporarily supports a wafer W tobe transferred, which is about to be loaded into the specific processchamber 4C, or the object supporting mechanism 58 for a contaminatedmember can support a wafer W which has to be unloaded and on which aprocess is completed. That is, two sheets of wafers W can besimultaneously supported in the whole pass portion 22.

Hereinafter, there will be described a method for transferring an objectto be processed in the processing system 50.

First, as described above, it is supposed that a process in whichcontamination can easily occur on a wafer is carried out in thespecified process chamber 4C. Further, in the respective carryingmechanisms 18 and 24, one pick, e.g., the pick 18A or 24A, is employedas a cleaning pick and only the other pick 18B or 24B is employed as acontamination pick. Further, operations of the loading carryingmechanism 16 are entirely identical to that described in FIG. 1 and,thus, the description thereof will be omitted.

It is assumed that processes are carried out on the semiconductor waferW in the process chamber 4E, the process chamber 4A, the process chamber4B, the specific process chamber 4C, the process chamber 4D, and theprocess chamber 4F in the order named. Further, the wafer W istransferred as indicated by arrows in FIG. 3. Also in this case, theroute used by the cleaning pick is represented by black arrows and theroute used by the contamination pick is indicated by white arrows.Moreover, as described above, since transferring operations are entirelyidentical in the loading transfer chamber 10 shown in FIGS. 1 and 3, thedescription thereof will be omitted.

<Transferring Operations in the Second Common Transfer Chamber 20>

First, there will be described wafer transferring operations in thesecond common transfer chamber 20.

1. First, the contamination pick 24B of the carrying mechanism 24 movesto pick the wafer W on which a process is completed in the processchamber 4F and puts it in the empty load lock chamber 8B for acontaminated member after moving along a transfer route Z1.

2. Then, the contamination pick 24B moves to pick a wafer W on which athin metal film has been deposited and which is supported on thesupporting pins 58B (see, FIGS. 4 and 5) of the object supportingmechanism 58 for a contaminated member in the pass portion 22, andtransfers it into the empty process chamber 4F after moving along atransfer route Z2. Thereafter, a process is started in the processchamber 4F.

3. Next, the cleaning pick 24A moves to pick a wafer W on which aprocess is completed in the process chamber 4E and puts it on both thesupporting plates 60A of the empty object supporting mechanisms 60 for aclean member in the pass portion 22 after moving along a transfer routeZ3. As shown in FIG. 5, the wafer W is supported at a higher position byboth the supporting plates 60A. Further, as described above, in thisstate, any one of the other two object supporting mechanisms 56 and 58can support another wafer W.

4. Next, the cleaning pick 24A moves to pick an unprocessed wafer W thatis standing by in the load lock chamber 8A for a clean member and loadsit into the empty process chamber 4E after moving along a transfer routeZ4. Thereafter, a process is started in the process chamber 4E. Further,when loading/unloading the semiconductor wafer W, the corresponding gatevalves 6 are operated to be opened/closed.

Furthermore, whenever the processes are completed on the semiconductorwafer W in the respective process chambers 4E and 4F, the aboveoperations are repeatedly carried out.

<Transferring Operations in the Common Transfer Chamber 2>

1. First, the contamination pick 18B of the carrying mechanism 18 movesto pick a wafer W on which a process is completed in the process chamber4D and puts it on the supporting pins 58B of the empty object supportingmechanism 58 for a contaminated member in the pass portion 22 aftermoving along a transfer route Y1. The wafer W put on the supporting pins58B is immediately transferred to the second common transfer chamber 20and, thus, portions on the supporting pins 58 become empty again.

2. Then, the contamination pick 18B moves to pick a wafer W on which aprocess is completed in the specified process chamber 4C and loads itinto the vacant process chamber 4D after moving along a transfer routeY2. Thereafter, a process is started in the process chamber 4D.

3. At this time, a wafer W1 on which a process is already completed inthe process chamber 4B before, is supported on the supporting pins 56B(see, FIGS. 4 and 5) of the object supporting mechanism 56 for bufferingin the pass portion 22 serving as a buffer mechanism. The contaminationpick 18B moves to pick a wafer W that is supported on the supportingpins 56B and loads it into the empty specified process chamber 4C aftermoving along a transfer route Y3. Thereafter, a process is started inthe specified process chamber 4C.

4. Then, the cleaning pick 18A moves to pick a wafer W on which aprocess is completed in the process chamber 4B and puts it on the emptysupporting pins 56B after moving along a transfer route Y4. The wafer Wis standing by there.

5. Next, the cleaning pick 18A moves to pick a wafer W on which aprocess is completed in the process chamber 4A and transfers it into theempty process chamber 4B after moving along a transfer route Y5.Thereafter, a process is started in the process chamber 4B.

6. Next, the cleaning pick 18A moves to pick an unprocessed wafer W thatis standing by while being supported by the supporting plates 60A of theobject supporting mechanism 60 for a clean member in the pass portion 22and loads it into the vacant process chamber 4A after moving along atransfer route Y6. Thereafter, a process is started in the processchamber 4A. Further, when loading/unloading the semiconductor wafer W,the corresponding gate valves 6 are operated to be opened/closed.

In addition, whenever the processes are completed on the semiconductorwafer W in the respective process chambers 4A to 4D, the aboveoperations are repeatedly carried out.

As described above, the contamination picks 16B, 18B and 24B have to beused in the steps of transferring a wafer W into the specified processchamber 4C and transferring the wafer which has a thin metal film formedthereon in the specified process chamber 4C to thereby most likely causemetal contamination. On the other hand, in the steps prior to the stepof transferring the wafer W, the cleaning picks 16A, 18A and 24A areused. By separately using the picks as described above, it becomespossible to prevent to the utmost cross contamination (contaminationtransmission) from occurring.

Further, the above transferring order is just an example and thetransferring order in the respective process chambers 4A to 4F is notlimited thereto. In every transfer route, right before loading a waferinto the specified process chamber, a wafer on which a process iscompleted in the process chamber of the former step is temporarilysupported by the object supporting mechanism 56 for buffering in thepass portion 22 and, at this time, the wafer is transferred between thecleaning pick 18A and the contamination pick 18B. Accordingly, asdescribed above, the cleaning pick 18A is prevented from beingcontaminated and, as a result, a wafer W before being processed in thespecified process chamber 4C can be prevented from being contaminated.

Further, in the present preferred embodiment, an openable and closablegate valve 6 is interposed between the pass portion 22 communicatingwith the second common transfer chamber 20 and the first common transferchamber 2. Furthermore, in order to prevent cross contamination fromoccurring by processing gases in the respective process chambers 4A to4F, opening/closing operations of the respective gate valves 6 arelimited when transferring a wafer. In the present preferred embodiment,the gate valve 6 is not opened in such a state that the process chamberscommunicate with each other. In other words, it is avoided that the gatevalves 6 of two or more process chambers are simultaneously opened and,thus, a plurality of process chambers communicate with each other eventemporarily.

As is generally known, employed as a processing gas are a gas which cancause cross contamination, a corrosion gas, a gas which becomesexplosive when mixed with another gas, and the like. Accordingly,generally, when the gate valves of the respective process chambers areopened, the inner pressures of the common transfer chambers 2 and 22become to be positive pressures, e.g., about 27 Pa (200 mTorr) higherthan that of the process chambers, by a nonreactive gas, e.g., a N₂ gas.Accordingly, even though the gate valve is opened, a remainingprocessing gas in the process chamber does not flow into the commontransfer chambers.

Further, in the present preferred embodiment, in order to certainlyprevent occurrence of contamination or the like, the gate valves of twoor more process chambers are not opened at the same time. For example,when both the common transfer chambers 2 and 20 do not communicate witheach other by closing the gate valve 6 disposed between the pass portion22 and the first common transfer chamber 2, the respective gate valves 6of the process chambers 4A to 4D connected to the first common transferchamber 2 are controlled such that only one gate valve among them isopened. Meanwhile, the respective gate valves 6 of the process chambersE and 4F and the load lock chambers 8A and 8B connected to the secondcommon transfer chamber 20 are also controlled such that only one gatevalve among them is opened.

With regard to this, when both the common transfer chambers 2 and 20communicate with each other by opening the gate valve 6 of the passportion 22, the respective gate valves 6 of all the process chambers 4Ato 4F and the load lock chambers 8A and 8B are controlled such that onlyone gate valve among them is opened.

Accordingly, since two or more process chambers can be hindered fromsimultaneously communicating with each other, it is possible to preventcross contamination created by processing gases, outflow of a corrosiongas and generation of an explosive gas due to mixing.

Further, in the processing system shown in FIG. 3, the gate valve 6 isdisposed in the pass portion 22 whereby the common transfer chambers 2and 20 can conveniently be made to communicate with each other orblocked from each other. However, the gate valve 6 may not be providedin the pass portion 22 when the possibility of cross contaminationinduced by processing gases is low. In this case, both the commontransfer chambers 2 and 20 always communicate with each other via thepass portion 22.

Furthermore, in the preferred embodiment, the pass portion 22 alsoserves as a buffer mechanism. However, the present invention is notlimited thereto, as described with reference to FIG. 2, the buffermechanism 38 may be additionally provided at one corner in the firstcommon transfer chamber 2. In this case, the pass portion 22 need notserve as a buffer mechanism. That is, the buffering object supportingmechanism 56 that plays a role of the buffer mechanism can be removedfrom the pass portion 22 shown in FIG. 4.

Moreover, in the preferred embodiment, the first and the second commontransfer chamber 2 and 20 have unoccupied portions capable of beingconnected to process chambers (sides of a polygon), to which the aboveprocess chambers are not connected. Small-sized process chambers forperforming a preheating, a cooling and the like of wafers can beconnected to the unoccupied portions capable of being connected toprocess chambers. Accordingly, in the preferred embodiment, the objectsupporting mechanisms 56, 58 and 60 are vertically disposed at multiplelevels in order to secure spaces for installing the small-sized processchambers. However, in case that small-sized process chambers need not beconnected to the common transfer chamber, as shown in FIG. 6, two buffermechanisms 62A and 62B identical to the buffer mechanism 38 describedwith reference to FIG. 2 may be disposed in parallel in the pass portion22.

In this case, the buffer mechanism 62A functions as an object supportingmechanism for a clean member, which relays a clean wafer W from thesecond common transfer chamber 20 to the first common transfer chamber2. Further, the buffer mechanism 62A functions as an object supportingmechanism for buffering and transfers a wafer W between the picks 18Aand 18B. The wafer is transferred in a manner that both functions do notconflict with each other. Further, the buffer mechanism 62B functions asan object supporting mechanism for a contaminated member, which relaysthe wafer W processed in the process chamber 4C from the first commontransfer chamber 2 to the second common transfer chamber 20. In thiscase, the transfer sequence is the same as that shown in FIG. 6.

Further, in the preferred embodiment, it is assumed that the wafer W ismounted on the tables in the load lock chambers 8A and 8B and then apreheating or a cooling of the wafer W is carried out. For this reason,the load lock chamber 8A is used exclusively for loading and the loadlock chamber 8B is used exclusively for unloading. However, when apreheating or a cooling of a wafer is not carried out in the load lockchambers, the buffer mechanism 38 described with reference to FIG. 2 canbe employed instead of the above tables. An area of front ends of thesupporting pins 44 of the buffer mechanism 38 have to be small. If thearea where a wafer W makes a contact with the front ends of thesupporting pins 44 is small, even though in case the unprocessed waferand the processed wafer are transferred via an identical load lockchamber, the wafer is relatively slightly damaged by crosscontamination. That is, in this case, only one load lock chamber can beused. Further, one transfer port is provided in the first commontransfer chamber 2 shown in FIG. 1 and the second common transferchamber 20 shown in FIG. 3.

In addition, though there is described an exemplary case where thesemiconductor wafer is used as the object in the preferred embodiment,the present invention can be applied to a case of processing an LCDsubstrate, a glass substrate or the like without being limited thereto.

While the invention has been shown and described with respect to thepreferred embodiments, it will be understood by those skilled in the artthat various changes and modifications may be without departing from thespirit and scope of the invention as defined in the following claims.

1. A method for transferring an object to be processed in a processingapparatus, which has a number of process chambers including a specifiedprocess chamber for performing a process subject to contamination on theobject; and a carrying mechanism having two picks, the methodcomprising: a plurality of carrying steps of sequentially transferringthe object from one chamber to another among the process chambers,wherein one pick of the two picks is used in carrying steps till rightbefore the object is loaded into the specified process chamber, and theother pick of the two picks is used in a carrying step of loading theobject into the specified process chamber and any subsequent carryingstep for the object.
 2. The method of claim 1, further comprising adelivery step of conveying the object from the one pick to the otherpick, the delivery step including the steps of: placing the object on abuffer mechanism by the one pick; and moving the other pick to pick theobject placed on the buffer mechanism.
 3. A method for transferring anobject to be processed in a vacuum processing apparatus, which has anumber of process chambers including a specified process chamber forperforming a process subject to contamination on the object; a commontransfer chamber which is connected in common to the respective processchambers; a carrying mechanism having two picks and provided in thecommon transfer chamber; a buffer mechanism for temporarily supportingthe object and provided in the common transfer chamber; and one or moretransfer ports for loading or unloading the object into or from thecommon transfer chamber, the method comprising: a plurality of carryingsteps in which the object is sequentially transferred from one chamberto another among the process chambers, wherein one pick of the two picksis used in carrying steps till right before the object is loaded intothe specified process chamber, and the other pick of the two picks isused in a carrying step of loading the object into the specified processchamber and any subsequent carrying step for the object; and a deliverystep of conveying the object from the one pick to the other pick byemploying the buffer mechanism.
 4. A method for transferring an objectto be processed in a processing system having plural vacuum processingapparatuses connected via one or more pass portions, each vacuumprocessing apparatus including a number of process chambers; a commontransfer chamber connected in common to the respective process chambers;and a carrying mechanism having two picks and provided in the commontransfer chamber, wherein one process chamber of the processing systemis a specified process chamber which performs a process subject tocontamination on an object to be processed; a buffer mechanism fortemporarily supporting the object is provided in a common transferchamber connected to the specified process chamber or in a pass portioncommunicating with the common transfer chamber; and one of commontransfer chamber is provided with one or more transfer ports for loadingor unloading the object thereinto or therefrom, the method comprising: aplurality of carrying steps in which the object is sequentiallytransferred from one chamber to another among the process chambers,wherein one pick of the two picks is used in carrying steps till rightbefore the object is loaded into the specified process chamber, and theother pick of the two picks is used in a carrying step of loading theobject into the specified process chamber and any subsequent carryingsteps for the object; and a delivery step of conveying the object fromsaid one pick to the other pick by employing the buffer mechanism. 5.The method of claim 4, wherein at least two object supporting mechanismsfor supporting the object are provided in the pass portion; the objectis supported by one of the object supporting mechanisms before beingloaded into the specified process chamber; and the object is supportedby another object supporting mechanism after being processed in thespecified process chamber.
 6. The method of claim, wherein the passportion is provided with a gate valve for controlling common transferchambers coupled via the pass portion to communicate with or to beisolated from each other; and each of the process chambers is providedwith a gate valve for controlling a common transfer chamber connectedthereto to communicate therewith or to be isolated therefrom; andwherein when the gate valve of the pass portion is closed, only one ofthe gate valves of process chambers connected to each common transferchamber which is isolated by the pass portion is selectively opened; andwhen the gate valve of the pass portion is opened, only one of the gatevalves of process chambers connected to common transfer chambers whichcommunicate with each other by the pass portion is selectively opened.7. The method of any one of claim 3, wherein the delivery step includesthe steps of: placing the object on the buffer mechanism by said onepick; and moving the other pick to pick the object placed on the buffermechanism.
 8. The method of claim 3, wherein the number of transferports is two, one of the transfer ports being used exclusively forloading and the other transfer port being used exclusively forunloading.
 9. The method of claim 8, wherein load lock chambers, eachhaving a vacuum state and an atmospheric pressure state alternatelytherein, are respectively connected to the two transfer ports via gatevalves; and a loading transfer chamber provided with a loading carryingmechanism having two picks is connected in common to load lock chambersvia gate valves; and wherein one pick of the loading carrying mechanismis used when the object is loaded from the loading transfer chamber tothe load lock chambers; and the other pick of the loading carryingmechanism is used when the object is unloaded from the load lockchambers to the loading transfer chamber.
 10. The method of claim 1,wherein a process of depositing a thin metal film on the object iscarried out in the specific process chamber.
 11. The method of claim 4,wherein the delivery step includes the steps of: placing the object onthe buffer mechanism by said one pick; and moving the other pick to pickthe object placed on the buffer mechanism.
 12. The method of claim 4,wherein the number of transfer ports is two, one of the transfer portsbeing used exclusively for loading and the other transfer port beingused exclusively for unloading.
 13. The method of claim 12, wherein loadlock chambers, each having a vacuum state and an atmospheric pressurestate alternately therein, are respectively connected to the twotransfer ports via gate valves; and a loading transfer chamber providedwith a loading carrying mechanism having two picks is connected incommon to load lock chambers via gate valves; and wherein one pick ofthe loading carrying mechanism is used when the object is loaded fromthe loading transfer chamber to the load lock chambers; and the otherpick of the loading carrying mechanism is used when the object isunloaded from the load lock chambers to the loading transfer chamber.14. The method of claim 3, wherein a process of depositing a thin metalfilm on the object is carried out in the specific process chamber. 15.The method of claim 4, wherein a process of depositing a thin metal filmon the object is carried out in the specific process chamber.